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windy1 / zeroconf-rs

zeroconf is a cross-platform library that wraps underlying ZeroConf/mDNS implementations such as Bonjour or Avahi, providing an easy and idiomatic way to both register and browse services.
MIT License
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Incorrect buffer size allocated for txt record #17

Closed kgrech closed 2 years ago

kgrech commented 2 years ago

Steps to reproduce (Macos Big Sur):

Create MdnsService service and insert a few records.

let mut service = MdnsService::new(service_type, announcer_options.port);
let mut txt_record = TxtRecord::new();
txt_record
    .insert("service-id", ""405d70a5-b17d-438c-a08b-84b3c0573689"")
    .unwrap();
txt_record
    .insert("port", "7787").as_str())
    .unwrap();
service.set_txt_record(txt_record);

On the client side (we are using python library zeroconf v0.36.8 as client) we receive the following:

properties={b'service-id': b'405d70a5-b17d-43', b'port': b'7787\x00\x00\x00\xe0\x07\n\n\xe5\xf9\x07\x00\xf0'}, interface_index=None)

It looks like the side of the property is always equals to 16.

It seems to me that the problem is around this line in TTxtRecord::insert. Maybe it should be

let value_size = mem::size_of_val(value.as_bytes()) as u8;

or probably even

let value_size = value.as_bytes().len();

?

windy1 commented 2 years ago

Sorry this took so long to address, I was able to reproduce the issue and your proposed fix was indeed the solution. You can get it in 0.10.5. Thanks!